New cassette and chain and suddenly the chain is slipping?

garyk72

Hi guys,

I recently changed my cassette, chain and front mech on my giant defy. All seemed fine for a while but today the chain seemed to slip half a pedal turn on the 3 largest sprockets at the back. This only seemed to happen when I was on the 34 chain ring and climbing and it didnt jump gears, just slipped? I also have new R500 wheels on the bike and it's fitted with tiagra 9 speed.

Any ideas?

Cheers
G

lc1981

Could it be that it's slipping on the chainring rather than the sprockets?

bobones

Worn chainring? Same happened to me a few weeks ago.

farrina

If all are new then unlikely to be due to worn teeth on cassette. Possibly a stiff link? Try rotating chain backwards and see if it runs smoothly. I suppose it might be a worn front chain ring but this is unusual (I have never worn a chain ring out in 35 years of cycling)?

Try the late great oracle here http://sheldonbrown.com/chains.html#wear

Regards

Alan

simon_masterson

Is your rear derailleur properly adjusted and working? This can cause what you describe; I know because one of mine is very old and the spring is shot; as a result it does not always return properly, making the derailleur sit awkwardly, slackening the chain and causing skipping. I highly, highly doubt it's your chainrings; I've worn them before to the point that the gaps from not meshing were so big you could practically stick your head in them, and I experienced no particular ill effects.

Having said that, a stiff link is also a distinct possibility.

slowbike

Where you joined the chain - could it be the link is stiff causing the chain to ride up over the teeth ?

smoggysteve

Worn chainring seems a valid reason, but does it happen on both rings? chances are you ride mainly on your big ring. If it still slips on only the higher I would suggest its more of a fine tuning problem with your barrel adjusters. Don't over complicate things. work your way backwards. Start with the most obvious fault and work backwards:-
Chain, cassette, crank, derailleurs, fine adjustment, you.

Fr Howie

Possible that the gear cable is not sliding smoothly. You might well not need to change it, but use some PTFE/Teflon lubricant on the cable to see if it free it up and fixes the problem.

Just started using 'Rock and Roll' on my cables and it seems to be the 'Mutt's Nuts'!

blablablacksheep

How do you use that rock and roll stuff? Ie do you just wipe it on exposed cables?

rolf_f

SmoggySteve wrote:

Worn chainring seems a valid reason, but does it happen on both rings? chances are you ride mainly on your big ring. If it still slips on only the higher I would suggest its more of a fine tuning problem with your barrel adjusters. Don't over complicate things. work your way backwards. Start with the most obvious fault and work backwards:-
Chain, cassette, crank, derailleurs, fine adjustment, you.

He says only on the small ring and when under power. Small ring, mile for mile, will wear out quicker than the large. I'd say the small ring is toast. Obviously checking adjustments is a no brainer but I doubt cable tension issues are suddenly causing slipping like that at exactly the same time that the chain has been swapped.

woodywmb

The front won't be at fault: it will be the back. The list of possibilities is long - stiff chain link, too tight Powerlink, worn chain, worn cassette teeth, misaligned mech, bent mech hanger, jockey float too distant from cogs, weakened derailleur spring, indexing slightly out, sticky inner cable. Work your way through the Sheldon Brown advice. If the chain and cassette are reasonably new, and there are no stiff links in the chain, and the gear cable is slipping easily through the outer, the problem could be that the chain is not wrapping tightly enough round the bigger cogs. The B tension screw lifts the mech up towards the cassette, in effect making the chain circle smaller and tighter round the lower gears.

garyk72

Cheers for all the advice guys. Turns out the new mech chain and cassette were fitted by a YTS retard at my no longer LBS! Took the bike to another local shop and its now back to the way it was before the new equipment, e.g running normally and smoothly without slipping.

If anyone out there is in the Southampton area and wants a good LBS don't bother with Cycle World. Their list of shoddy work on my bike is far longer than this one cock up by the way.

farrina

Having followed this thread for some time are you not going to tell us exactly what was wrong ?

Regards

Alan ( on tenderhooks)

garyk72

Okay, I'll start from the start!

My bike needed a new chain, cassette, front mech and wheels. All of which were fitted at a not inconsiderable cost by the above mentioned LBS. Once I got the bike home the issues began. The front mech was always rubbing on the chain, this turned out to be because someone had fitted a 10 speed tiagra mech to my 9 speed tiagra drive chain!This took two visits to be worked out by the "mechanic". I was also told that he had adjusted the indexing to make things run smoothly again. So after another visit to have the spokes on my wheels properly tightened after they went out of true after 2 days I returned home looking forward to actually trying out my new kit properly. Then the chain started slipping!!

Once the bike had been seen by a good reputable LBS (Chase Cycles in Waltham Chase, Hampshire) it was discovered that the B screw was adjusted way too loose. The indexing was all over the place and to put the icing on the cake my rear mech was bent inwards. I have never dropped the bike and the rear mech was straight the last time I had the bike serviced. This combination was causing the chain to slip.

All sorted now though so onwards and upwards with riding my bike, starting with the Wiggle new forest spring sportive this weekend.

G

farrina

Gosh what a disaster and litany of faults. The bent rear hanger almost makes one wonder if the bike shop has hurled it against a wall.

I think we would have taken for ever trying to work out what was wrong with all that going wrong. Pleased now sorted though.

May the sun shine on you during the weekend, you float up the hills and descend like a train.

Cheers

Alan

woodywmb

Woodywmb wrote:

... the B tension screw lifts the mech up towards the cassette, in effect making the chain circle smaller and tighter round the lower gears.

+ bent rear hanger.

Sorted.